Electric Motors Do Work!
Electric Motors The computer you are viewing this page with, the electric razor you shaved with, the car you recently rode in, the elevator you took, the pencil sharpener at your desk, all share a unique and vital feature that their proper functioning is dependent on. Can you guess it? All of them have....drum roll...electric motors! Basically any appliance, in and outside of the home, that does work, has an electric motor. But what exactly is an electric motor, you ask?.... 'General Descritption' Electric motors are devices that convert electrical energy into mechanical energy. The electrical enerrgy is the electic current that is being generated from a particualr power source. These sources of energy can be chemical, solar,nuclear, water hydrodynamic), or even wind. This energy is measured in Watts (Voltage x Amperes). The mechanical energy, or the kinetic energy, is motion that results from the flow of the electric current through the motor as it reacts with the natural forces of the magentic field (the motor contains magnets that repel each other and inturn rotate in a ciruclar motion). This kind of energy is measured in horsepower (foot-pounds/second). Essentially, a motor uses the forces of the magentic field to take an electrical current being fed into the motor, and convert it into mechanical motion to do work. note!: Be careful not to confuse an electric motor with a generator. When placed side by side, they are seemingly identical by appearance. But in fact, their jobs are exact opposites. A generator creates electrical engery from mechancial energy, while a motor turns electrical energy into mechancial. The motor actaully depends on the generator as a source of electricla current. History In 1819, Hans Christian Oersted discovered that each time he brought a compass near a current carrying conductor (anything that absorbs electrical charge), the compass would move to become perpendicular to the conductor. Michael Farady continued to research this idea, and he found that motion could be created using the magentic field. Farady created the first electric motor in 1821. However, while Farady's invention had great potential, it didn't have enough power and thus usage for everyday life. Thomas Davenport went on to revise Farady's model of the motor, and in 1837 he recieved the first U.S. patent for one. However, during his lfitiem, Devenport did not recieve the great reocngintion he deserved. At the time, generators had not been invtnened yet, so the motors lacked the powerful electicity that they needed. Thus, the motor had no real value for commericial appliances, and Davenport could not obtain success with his creation.After he had died, however, in 1837 Davenport's motor was exhibited in Berlin as the firts mtor to be used for industrial/commerical applications. since then, our use of the motor has entered our homes, our work place and everywhere between. Motors have become a crucial part of everyday living, although many have yet to relaize it. How Do They Operate? Electric Motor operation is based on the principles of electromagnetism. Two electromagents, one that is stationary on a stator, and one that can rotate on a rotor, are placed inside the motor's frame. A motor can use permanent magents (suchas bar magnets), but they generally have electromagnets made of a coil of copper wire that acts as a conducotr and becomes magnetized when current flows through it. Electricity moves from a soruce (perhpas a batter or an outlet), and through the wire of the particualr appliance. The current reaches the morot, and is fed to eahc of the magents. It flows form the wire to the rotary electromagnet, and to the staionary electromagnet via a brush, which is often a small piece of carbon that a magnetic field is created around eahc of them, and they become instantly replled or attracted as the current flows trhough eahc of their copper bodies in opposite directions, creating opposite poles. The inner-most electromagent, on the rotor, spins, trying to get to, or get away form, the pole of the other magnet. This rotation is what alows the motor do work, and is the actaul mehcnanical enegry that has been produced. DC (Direct Current) Motors AC (Alternating Current) Single Phase Motors AC Polyphase Motors Speed Power Factor Why Do We Use Them? References Resources